Having trouble getting postfix configured correctly to relay to Google Apps some of the time.
I am seeing the following error in /var/log/mail.log Dec 8 21:15:08 vps postfix/master[3924]: daemon started -- version 2.9.3, configuration /etc/postfix Dec 8 21:16:05 vps postfix/smtpd[3930]: warning: hostname vps.abw.co does not resolve to address 199.101.51.160 Dec 8 21:16:05 vps postfix/smtpd[3930]: connect from unknown[199.101.51.160] Dec 8 21:16:05 vps postfix/smtpd[3930]: lost connection after RSET from unknown[199.101.51.160] Dec 8 21:16:05 vps postfix/smtpd[3930]: disconnect from unknown[199.101.51.160] If I use a sendmail command from the CLI I am able to send with a 250 response code. I only see the other error when using php and phpmailer. Since that makes it probably a phpmailer issue what things could be set incorrectly there that would cause postfix to log the errors listed above I have tried removing vps.abw.co from my destination with the same result. 199.101.51.160 is my server IP vps.abw.co is my server hostname RDNS is set correctly: host 199.101.51.160 160.51.101.199.in-addr.arpa domain name pointer vps.abw.co postconf -n alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases append_dot_mydomain = no biff = no config_directory = /etc/postfix default_destination_concurrency_limit = 5 default_transport = smtp inet_interfaces = all inet_protocols = ipv4 mailbox_command = procmail -a "$EXTENSION" mailbox_size_limit = 51200000 mydestination = vps.abw.co, localhost.abw.co, localhost myhostname = vps.abw.co mynetworks = 127.0.0.0/8 readme_directory = no recipient_delimiter = + relay_destination_concurrency_limit = 1 relay_transport = relay relayhost = smtp.gmail.com:587 smtp_connection_cache_destinations = smtp.gmail.com smtp_sasl_auth_enable = yes smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd smtp_sasl_security_options = noanonymous smtp_sasl_tls_security_options = noanonymous smtp_tls_security_level = may smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) smtpd_tls_CAfile = /root/ssl/ca.pem smtpd_tls_ask_ccert = yes smtpd_tls_cert_file = /root/ssl/ssl.crt smtpd_tls_key_file = /root/ssl/ssl.key smtpd_tls_loglevel = 1 smtpd_tls_received_header = yes smtpd_tls_req_ccert = no smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtpd_tls_session_cache_timeout = 3600s smtpd_use_tls = yes Thanks, Cameron Smith